Placed in Procyon pygmaeus according to Merriam (1901), (Goldman 1950), Hall (1981), Lazell (1981), and Helgen and Wilson (2005). Body size and cranial characters have been sufficient to consider P. pygmaeus a separate species (Merriam 1901, Goldman 1950, Jones and Lawlor 1965). Morphometric data from McFadden (2004) and García-Vasco (2005) supports that the Pygmy Raccoon is a true dwarf and a separate species. Analysis of mtDNA indicates that this species is genetically distinct from the Yucatan Peninsula P. lotor (i.e., the closest congeneric populations; McFadden et al. 2008). Helgen and Wilson (2003) consider P. pygmaeus to be the only valid taxon among the insular raccoons from the Caribbean.

Justification:
This species meets criterion C to be listed as Critically Endangered:

Criterion C: Small population size and declineNumber of mature individuals is less than 250: based on the estimates of population size including juveniles [323-955], and the fact that it has been estimated that 59% of the population corresponds to mature individuals, we estimate a number of mature individuals that ranges from [192-567]. Following the precautionary principle of using the lower limits, the population size of mature individuals is much less than 250 mature individuals.

And

C2: a continuing decline on the population size due to the effects of introduced species and (a i). Less than 50 mature individuals in all subpopulations: The average estimated population size and standard error for all pygmy raccoon subpopulations is 27.8 ± 5.5 individuals. (a ii). At least 90% of mature individuals in one subpopulation subcriterion is not met because abundance estimates range from a low of 16 individuals (95% CI= 13-20) to a high of 48 individuals (95% CI = 39-79).(b) Extreme fluctuations in the number of mature individuals due to the effect of hurricanes (in this part of the Caribbean hurricanes occur on average once every 8 years).

In addition, the species meets criterion B to be listed as Endangered:

Criterion B: Geographic rangeB1: Extent of occurrence of 478 km² is much less than 5,000 km².B2: Area of occupancy is much less than 500 km² (if the EOO is 478 km² the AOO must be less than this value); (a) less than 5 locations [1 location];(b) continuing decline in number of mature individuals due to the effect of introduced alien taxa to the island; (c) extreme fluctuations in the number of mature individuals due to the effect of hurricanes.

Total population estimates for P. pygmaeus, including juveniles, range from 323 (McFadden 2004) to a maximum of 955 individuals, including juveniles (Copa-Alvaro 2007). During 2006, a total of 105 different known individuals, including juveniles, were caught indicating that the total P. pygmaeus population is comprised by at least this number (Copa-Alvaro 2007). Considering that 59.4% of captured individuals are adults (McFadden et al. in review), then the estimated number of mature individuals ranges from 192 to 567 (62, when one considers the minimum number of known individuals). The average estimated population size and standard error for all pygmy raccoon subpopulations is 27.8 ± 5.5 individuals (McFadden et al. in review). Abundance estimates for the best known populations range from a low of 16 individuals (95% CI= 13-20) to a high of 48 individuals (95% CI = 39-79; McFadden et al. in review). Density estimates vary between sites and year of study, and range from 12.4 to 112 individuals/km² (Copa-Alvaro 2007, McFadden 2004). A sexual proportion lightly skewed to females was recorded but was not significantly different from 1:1 (García-Vasco 2005).

The species is severely impacted by hurricanes and already depressed populations from a variety of human threats make it increasingly difficult for populations to recover following natural disasters. After major hurricanes, the density of pygmy raccoons can decline at a particular site by as much as 60% and the proportion of juveniles in the population can diminish significantly (Copa-Alvaro 2007). The impact of hurricanes may vary among regions or vegetation types on the island (Copa-Alvaro 2007).

Information on the ecology of the Pygmy Raccoon has been summarized in Cuarón et al. (2004), McFadden (2004), and de Villa-Meza et al. (in press). The Pygmy Raccoon prefers mangrove stands and sandy areas, but they are also found in semi-evergreen and subdeciduous tropical forests and agricultural areas. Abundance varies considerable among vegetation types. Main subpopulations are restricted to coastal areas of the island, and vast areas of the central part of the island are uninhabited or have very sparse subpopulations. The Pygmy Raccoon may inhabit areas that are in proximity to human settlements, as well as to paved and unpaved roads (Cuarón et al. 2004, McFadden 2004, García-Vasco 2005, Copa-Alvaro 2007).

Pygmy Raccoons are mainly nocturnal, although it is not uncommon to see them during daylight (Cuarón et al. 2004, García-Vasco 2005). Generally it is a solitary mammal, which could sometimes form family groups (Cuarón et al. 2004, Jones and Lawlor 1965).

The Pygmy Raccoon is an omnivorous species, with preference for crabs but followed by fruits, insects, crayfish, and small vertebrates (McFadden et al. 2006, Martínez-Godinez 2008). The relevance of the different food items varied importantly between seasons and sites, and following major changes in habitat quality due to hurricanes (McFadden et al. 2006, Martínez-Godinez 2008).

The Pygmy Raccoon is particularly vulnerable to introduced pathogens and diseases such as mange, rabies and dog distemper from exotic animals (Cuarón et al. 2004, McFadden 2004, Mena 2007). The parasites Eimeria nutalli, Placoconus lotoris, Capillaria procyonis, Physaloptera sp., a mite in the family Listrophoridae, and a trematode in the family Heterophyidae have been collected from P. pygmaeus individuals (McFadden et al. 2005). The identification of Toxoplasma gondii in some Pygmy Raccoons suggests a recent spillover from domestic cats (McFadden et al. 2005). It has been identified that the Pygmy Raccoon has been exposed to infectious canine hepatitis, canine distemper and feline panleukopenia viruses (McFadden et al. 2005, Mena 2007).

Genetic information indicates that Pygmy Raccoon individuals share the same mtDNA haplotypes, suggesting a recent population bottleneck that might be related to the founder effect (McFadden et al. 2008).

Cozumel Island has been substantially developed for tourism. Cozumel is still relatively well-conserved, with close to 90% of the island covered by natural vegetation (Romero-Nájera 2004, Romero-Nájera et al. 2007), but the situation is deteriorating rapidly. The interior of the island is less developed, but raccoons are rare or absent there (Cuarón et al. 2004, García-Vasco 2005, Copa-Alvaro 2007). There is only a very small area of prime raccoon habitat and this is on the coast where most of the tourist development is taking place.

The expansion and widening of the road system is fragmenting the vegetation of the island in at least three areas (Cuarón et al. 2004, de Villa-Meza et al. in press). The widening of roads is potentially increasing their barrier effect and exacerbating their impact on the conservation of Pygmy Raccoons and other native species (de Villa-Meza et al. in press). Most cases of Pygmy Raccoon mortality documented since 2001 have been the result of animals being run over by cars on the island's highways (García-Vasco 2005).

Alien invasive predators, such as Boa constrictor, as well as domestic and feral dogs, may have an important impact on the Pygmy Raccoon population and it is confirmed that feral dogs predate on them (Martínez-Morales and Cuarón 1999, García-Vasco 2005, Bautista 2006). Additionally, introduced carnivores to the island could easily become a source of parasites and pathogens that could potentially affect negatively Pygmy Raccoon populations (Cuarón et al. 2004, McFadden et al. 2005, Mena 2007). The introduction of congeners from the mainland (P. lotor), usually for pets, is a risk of genetic introgression and a potential source of parasites and pathogens (Cuarón et al. 2004).

Hurricanes are the main natural threat recognized for the Cozumel biota (Cuarón et al. 2004, Perdomo 2006, Barillas 2007, Copa-Alvaro 2007). In the case of the pygmy raccoon, hurricanes cause drastic population decline, reduction in the proportion of juveniles, and cause injury and facilitate pathological change (Copa-Alvaro 2007, Mena 2007). The frequency, magnitude and duration of hurricanes in the Caribbean Basin is increasing (CITA), so they are an issue of major concern as there may be a synergistic effect with anthropogenic disturbance.

Hunting and collection of Pygmy Raccoons as pets is currently not an important threat.

The Pygmy Raccoon is legally protected in Mexico. It is included in the official Mexican list of threatened species as "En Peligro de Extinción" (SEMARNAT 2002). An island-wide ecological ordinance program (Programa de Ordenamiento Ecologico Local) that seeks to determine the pattern of land occupation, minimizing conflict and maximizing consensus among stakeholders, has recently been implemented and is in the process of being officially decreed. There are initiatives underway to establish two new protected areas on Cozumel Island. An invasive alien animal control programme is underway on Cozumel Island. This program has focused primarily on urban stray dogs and cats, and it is necessary to expand it to feral dogs and cats, house rats and mice, and Boa constrictor. There is work in progress for the establishment of a captive breeding program. An environmental education programme promotes the conservation of Cozumel endemic biota. A long term initiative for the study and conservation of Cozumel's native biota has been undertaken, promoted and sustained by a Mexican interdisciplinary multi-institutional team.